Topband: 1/8 wave vertical

[Tom Rauch]

The most difficult to deal with loss in a vertical antenna, 
once it is 1/8th wave tall or taller, is in the ground 
system. While it is possible to do something wrong, like 
make the antenna out of a thin resistive conductor or use an 
exceptionally bad loading system design, if even reasonable 
care is taken or with reasonable selection of materials most 
of the loss is in the ground system.

If the ground system is very good then there is almost no 
difference at all between top loading, center loading, or 
base loading. The exception would be a poor loading coil 
design, for example a coil that was approaching 
self-resonance at the operating frequency. A loading coil 
self-resonant on 4 MHz would not be a good loading coil on 
160 no matter how the inductor was constructed.

Follow the rules of common sense...use a big hat or 
something with some self-capacitance near the top. Use 
space-wound turns and a good form factor on the coil with 
reasonable size wire. Use a good ground system. The result 
will be almost no difference at all between a 150 foot 
vertical and a 50 foot vertical.

Do things wrong and height can make a great difference.

73 Tom